A NOVEL CARBON PROCESS.--Mr. O. Volkner publishes the following dust
carbon printing process, which appears to be easy to carry out, requires
no reversed negatives, and yields permanent prints. We also think it can
be used in making phototypic printing blocks. Make a solution of
gelatine in water 1–60, and draw sheets of good strong paper through it,
and hang it up to dry. Wet it again and squeeze it down on a piece of
glass. Now brush over it a solution of ten parts gelatine, ten parts gum
arabic, twenty parts white sugar, eighty parts distilled water. While
still quite moist put it in a dusting box (such as used for
photogravure) which contains a mixture of 100 parts of white dry sugar
and five parts of French lamp black. After a lapse of eight to ten
minutes, withdraw it and you will find it covered with innumerable
particles of dust. Paper thus prepared will keep, and has to be
sensitized in a bath of fifty parts bichromate of potassium, fifty parts
bichromate of ammonia, six thousand parts water and aqua ammonia, until
it assumes a light yellow color, and at last, to avoid the too quick
dissolution of the gum arabic, immerse in twenty parts chromic acid in
1,500 alcohol. Print by Vogel’s photometer 16° to 18°. To develop, use
warm water first, and afterwards cold, leaving the print for several
hours in water, to which may be added a little aqua ammonia, in case the
printing was carried too far. The prints show a singular and very
pleasing grain and need no transferring.--_Dr. Eder’s Jahrbuch._
* * * * *
EVERY photographer is, no doubt, to his own sorrow, familiar with a
yellow stain in the negative, caused by taking the plate from the fixing
bath before it is thoroughly fixed. Mr. Belitski, the well-known
photo-chemist, made some experiments recently to remove this stain, and
succeeded very well. A slight stain can often be removed by placing the
negative in the following solution: 50 parts alum, 1000 parts water, 10
parts bichromate of potassium, 20 parts muriatic acid. After several
minutes the negative turns yellow all through. It is washed now very
thoroughly, exposed to sunlight for several minutes, and developed or
blackened with the ordinary iron developer. When the stain is very
intense this remedy will not prove to be of any avail, and only by
leaving it for twenty-four hours in the Lainer acid fixing bath (so
often described in all journals recently) he succeeded in removing the
stain and saving a valuable negative.--_Deutsche Photographen Zeitung._
* * * * *
THE article on “Fixing Plates” which appeared in our June number, page
163 should read in the heading “Fixing Prints.” Our readers have
doubtless discovered this for themselves before now.
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